sickswan Posted February 18, 2015 Report Share Posted February 18, 2015 So I purchased a set of mz forks for my bsa c15 trials bike I'm building problem is my 35mm yokes are just that 35mm an the mz forks are 34.7 the options at the minute are shim out the gap using 6 tho shim wrapped round the stancions or bore out the yokes and turn a split bush. Re chroming is not an option as I don't even know if the forks are any good so don't want to waste 150 quid re hard chroming them.. any input welcome Quote Link to comment Share on other sites More sharing options...
totalshell Posted February 18, 2015 Report Share Posted February 18, 2015 i would nt bore out the yokes if your unsure of the forks. your shim to make up the difference would be the thickness of a piece of paper... careful though if you fold that piece of paper in half 103 times it would be as thick as the universe. http://www.sciencealert.com/a-piece-of-paper-folded-103-times-will-be-as-thick-as-the-universe 2 Quote Link to comment Share on other sites More sharing options...
craigrushton Posted February 18, 2015 Report Share Posted February 18, 2015 Would get some .006" shim steel as you said and try, should be ok and tighten up nicley ! "fold that piece of paper in half 103 times it would be as thick as the universe." !!!!! WOW ! Quote Link to comment Share on other sites More sharing options...
trialsrfun Posted February 18, 2015 Report Share Posted February 18, 2015 totalshell, on 18 Feb 2015 - 06:24 AM, said: i would nt bore out the yokes if your unsure of the forks. your shim to make up the difference would be the thickness of a piece of paper... careful though if you fold that piece of paper in half 103 times it would be as thick as the universe. http://www.sciencealert.com/a-piece-of-paper-folded-103-times-will-be-as-thick-as-the-universe Go for it but please let us know the outcome. Quote Link to comment Share on other sites More sharing options...
b40rt Posted February 18, 2015 Report Share Posted February 18, 2015 Buy some billet yikes to suit, you know you want to. Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted February 18, 2015 Report Share Posted February 18, 2015 (edited) I had exactly the same problem with some Suzuki beamish forks, they are also just under 35mm I now use some steel shim, it works a treat (it’s a pain fitting it in though!) If the forks are under 35mm and you have them re-chromed to 35mm you would also need to modifiy the bushes in the legs as they wouldn’t fit! Edited February 18, 2015 by suzuki250 Quote Link to comment Share on other sites More sharing options...
sickswan Posted February 18, 2015 Author Report Share Posted February 18, 2015 Thanks for the help guys managed to shim out the top with 4 tho system shim an the bottom with 3 tho plastic shim we use behind broach cutters at work.. jobs a good un! As for the billet yokes they are billet yokes I've had made up by a bloke at work only thing is I presumed the 35mm forks were 35mm. And I suggest anyone who tries folding the paper that many times is very careful do it wrong and you will create a black hole and we'll all be sacked in.. Quote Link to comment Share on other sites More sharing options...
sickswan Posted February 18, 2015 Author Report Share Posted February 18, 2015 Steel shim not system lol Quote Link to comment Share on other sites More sharing options...
bobb Posted February 21, 2015 Report Share Posted February 21, 2015 i did the same used a shim to get 34mm yamaha forks to fit into a 35mm yoke it works perfect Quote Link to comment Share on other sites More sharing options...
sickswan Posted March 16, 2015 Author Report Share Posted March 16, 2015 Right so the bike is together and forks work really well only problem now is fork seals are spewing oil out which I could have guessed would happen as they are 35mm seals found in our stores at work.. any ideas with out sending them for re chroming??? Are the mz seals smaller than 35mm??? Only imperial size round ther is 1 3/8 which is 34.9ish so prob still same problem??? Anyone any ideas??? Quote Link to comment Share on other sites More sharing options...
b40rt Posted March 16, 2015 Report Share Posted March 16, 2015 http://www.ebay.co.uk/sch/i.html?_odkw=m+z+fork+seals&_osacat=0&ssPageName=GSTL&_from=R40&_trksid=p2045573.m570.l1311.R-1.TR3.TRC2.A0.H0.Xm+z+fo.TRS0&_nkw=mz+forks&ghostText=&_sacat=0 Quote Link to comment Share on other sites More sharing options...
ducman Posted March 17, 2015 Report Share Posted March 17, 2015 Just a thought, why use MZ-Forks with this starnge diameter. Our west german army bikes(Hercules K 125 V1 and K 180)used 35 mm Marzocchi.A lot of classic trials riders use them in their bikes here on the continent and also in the UK.Cheap,and parts are easy to get.So why go east,stay west. 3 Quote Link to comment Share on other sites More sharing options...
bashplate Posted March 17, 2015 Report Share Posted March 17, 2015 sickswan, if you just used 'ordinary' oil seals then even if right size they will leak. You have to use proper fork seals....I know all this because I had the same problem with a set of Ossa forks, fitted proper seals (for a ktm I think) and all was good. 1 Quote Link to comment Share on other sites More sharing options...
lbhbul Posted March 17, 2015 Report Share Posted March 17, 2015 (edited) What bashplate said!! You may not be able to get seals to hold .012 small? Worth a try as this is kinda where your at. When you get the proper seals a help that was taught to me ; take the spring out of the seal & unscrew it & cut 1/4 inch off the female end & screw it back together, you will find that it is now a good fit on the stanchion whereas before cutting it was a sloppy fit, reassemble seal & spring & proceed. Hope this helps, it works for me. Larry As an aside I noticed on the link b40rt gave, off on the RH side are a complete Ossa 35 mm forks for bid, not too much time left. Edited March 17, 2015 by lbhbul 1 Quote Link to comment Share on other sites More sharing options...
fernacticus Posted December 7, 2022 Report Share Posted December 7, 2022 I have MZ forks on my Tiger Cub. The size thing is a right pain! I currently have mine shimmed with bits of feeler gauge which is working ok. As for the leaking, Mine were awful so I bought a pair of tubes and seals from somewhere in Germany, One of the MZ dealers) for about £100 delivered. Still no leaks. The price will have gone up a bit since Brexit, Covid, the war, bird flu etc etc! Quote Link to comment Share on other sites More sharing options...
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